I. Field of the Invention
The present invention relates generally to pushbutton switch devices and, more particularly, to pushbutton switch devices in which electrical contact is made in a control circuit when the switch plunger is advanced. The switch provides a momentary signal in a circuit that initiates an action which continues after the momentary push of the button has been released. Many coordinated switches may be mounted in a panel array with corresponding pushbuttons such as in elevator controls and, specifically, the switch devices of the invention feature mounting elements that insure proper alignment and are configured to prevent rotation of the pushbutton relative to the housing.
II. Related Art
A variety of pushbutton switch devices have been developed in which a pushbutton is connected to a central plunger that is longitudinally moveable in a barrel to contact and momentarily connect and thereby activate a control circuit upon depressing the plunger and in which contact is broken upon release and retraction of the pushbutton and plunger. Such switches find utility a variety of applications in which the pushbutton switch provides activation for a momentary signal to a circuit that initiates some action which continues after a momentary push of the button has been released. Such a sequence is well known. For example, in elevator controls where pushbuttons associated with each floor are used to log in and activate the operation of the elevator accordingly.
Such pushbutton switches are known which may have a construction which precludes or controls rotation of the pushbutton in its housing. Such a device is shown, for example, in U.S. Pat. No. 6,191,376 B1 to Bartok in which spaced lugs engage splines with a ratchet to index rotation of the pushbutton to alternately connect and disconnect a circuit.
Many other pushbuttons of the class are constructed so that the pushbutton and plunger are free to rotate at random. In addition, such prior devices require periodic lubrication to assure continued operation.
Thus, there remains a need for a simple, but long life, pushbutton switch actuating device which includes an anti-rotation feature and which does not require lubrication for the life of the pushbutton.